1. Field of the Invention
Embodiments of the present invention relate to methods and systems for zonal isolation, where a zone isolation composition is pumped into an annulus between a borehole and a tubular member allowed to set to form an isolation seal, where the seal has a compressibility sufficient for expandable tubing to be expanded without loss in seal integrity. The cured compositions are ideally suited for use with expansion tubing, where the zonal isolation composition must be compressible, while continuing to isolate the zones.
More particularly, embodiments of the present invention relate to methods and systems for zonal isolation, where the zone isolation composition is pumped into an annulus between a borehole and a tubular member allowed to test to form an isolation seal, where the seal has a compressibility sufficient for expandable tubing to be expanded without loss in seal integrity. The composition includes epoxy resins and hardening agents in the presence or absence of a solvent or solubilizing agent. The invention contemplates different combination of the resins, hardening agents and solubilizing agents for different temperature application: a low temperature zonal isolation composition, a moderate temperature isolation composition and a high temperature isolation composition, where the low temperature composition sets at a low temperature range, the moderate temperature composition set at a moderate temperature range and the high temperature composition sets at a high temperature range. All of the compositions cure to form a compressible zonal isolation epoxy seal capable of use with expansion tubing.
2. Description of the Related Art
Conventional sealants for zonal isolation are cements, foam fluids or resins. In expandable tubing applications, the zonal isolation sealant must be able to compress and to continue to seal after the sealant is pumped behind the pipe and set. Conventional zone isolation systems do not offer the compressibility and/or resilience necessary to permit expandable pipe to expand without fracturing the system due to their hardness obviating zonal isolation. Expandable pipe must, therefore, be expanded prior to the sealant setting. This requires retarding the setting of the sealant for a time sufficient to permit the expandable pipe to be expanded prior to sealant setting. Once the tubing is expanded, the sealant sets. Problems arise when expansion of expandable tubing cannot occur within the retarding window for once the sealant sets, the expandable tubing cannot be expanded due the incompressibility of the cured sealant.
Thus, there is a need in the art for a sealant that is compressible and/or resilient permitting expandable tubing to be expanded before, during and/or after sealant curing. The solution to these problems is a sealant that is compressible or resilient enough to allow expansion of the expandable pipe before, during or after the material has harden.